1. Field of the Invention
The present invention relates to an antenna assembly, and more particularly, to an antenna assembly capable of minimizing interference of antennas for communication services.
2. Discussion of the Related Art
Generally, a repeater for mobile communication services includes a receiver antenna (donor antenna) and a transmitter antenna (coverage antenna).
Such an antenna includes a radiator and a reflector.
The radiator radiates or absorbs radio waves to/from subscriber's terminals in a communication service area.
The reflector is attached to a rear side of the radiator, to reflect the radio waves radiated from the radiator to the subscriber's terminals, or to reflect the radio waves absorbed by the subscriber's terminals.
Each antenna of a conventional repeater for mobile communication services which has the above-mentioned configuration, exhibits radiation patterns having front-to-back ratio (FTBR) characteristics and front-to-side ratio (FTSR) characteristics as shown in FIG. 1, due to scattering waves occurring at the edge of the reflector of the antenna. The radiation patterns having FTBR characteristics are back-lobes, whereas the radiation patterns having FTSR characteristics are side-lobes.
For this reason, the receiver antenna and transmitter antenna of the conventional repeater radiate a large amount of waves in lateral directions and in a back direction. As a result, signal interference occurs between the receiver antenna and the transmitter antenna.
In order to suppress such signal interference occurring between the receiver antenna and the transmitter antenna, a sufficient isolability must be secured between the two antennas. In order to secure a sufficient isolability, the receiver antenna and transmitter antenna in the above-mentioned conventional repeater for mobile communication services are arranged such that they are directed in opposite directions (180°-spaced directions). Also, a certain obstacle is placed between the receiver antenna and the transmitter antenna. Alternatively, the receiver antenna and transmitter antenna are spaced apart from each other by a sufficient distance. That is, the conventional repeater must be designed, taking into consideration the signal interference occurring between the receiver antenna and the transmitter antenna. For this reason, there is a difficulty in installing the antennas.